Parking space size requirements are different for manually driven vehicles and self-driving vehicles. Vehicles that are parking without human occupants can optimize parking space usage by parking extremely close to one another. Without humans, there is no need to be able to open the doors. Additionally, self-driving vehicles can maneuver extremely close to one another without colliding. In a mixed parking environment, if a self-driving vehicle parks too close to a vehicle with human occupants, there will be problems for the occupants when exiting the vehicle or when driving away from the parking space.